Jacquec, It seems like most people half answered your question. Pumps are okay to run all year as long as they don't freeze up. Having good water movement will help prevent anaerobic decay of organic materials. If there is a bad smell in your water this is a big sign you have anaerobic decay. That is the bad stuff that harms fish because it contains bad bacteria. By having water movement and air introduced into your water you will avoid that. I used to start my pumps in early March but now keep them running all winter. The second part of your question was filtration. That can be added after the pumps are started. If your fish aren't moving much then you don't need it but once they get more active then you want to put them in so good bacteria has a place to grow. It need to be at least 55 degrees for the bacteria to survive. I usually let my pond cycle before giving them much food. This usually takes about a month but is dependent on temps and other factors. It takes a while for the natural bacteria to build up that will process ammonia and nitrites. Feeding them a lot just compounds the problem because ammonia levels will skyrocket without the good bacteria. Also if it is early in the year you can have a problem with nitrates if your plants haven't started growing.